/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 刘国水
 * Date: 2025-04-16
 * Time: 22:13
 */
public class MySingleList implements ILinkedList{

    //定义内部类 表示 节点对象
    static class ListNode{
        //数据
        public int val;
        //节点的引用
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }

    }

    public ListNode head;

    @Override
    public void addFirst(int data) {
      ListNode node = new ListNode(data);
      node.next = head;
      head = node;
    }

    public void createList() {

    }


    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        //先判断head是否为空
        if(head == null) {
            head = node;
        }
        ListNode cur = head;
        while (cur != null) {
            cur = cur.next;
        }
        cur.next = head;
    }

    @Override
    public void addIndex(int index, int data) {
        checkPos(index);
        if(index == 0) {
            addFirst(data);
            return;
        }
        if(index == size()) {
            addLast(data);
            return;
        }

        ListNode cur = findIndex(index);
        ListNode node = new ListNode(index);
        node.next = cur.next;
        cur.next = node;

    }

    private ListNode findIndex(int index) {
        ListNode cur = head;
        int count = 0;
        while (count != size()-1) {
            cur = cur.next;
            count++;
        }
        return cur;
    }
    private void checkPos(int index) {
        if(index < 0||index > size()) {
            throw new CheckPosException("index位置不合法：" + index);
        }
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null) {
            if(cur.val == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if(head == null) {
            System.out.println("链表为空，无法进行删除！");
            return;
        }

        if(head.val == key) {
            head = head.next;
            return;
        }

        ListNode cur = search(key);
        if(cur == null) {
            System.out.println("没有你要删除的数据" + key);
            return;
        }
        ListNode del = cur.next;
        cur.next = del.next;
    }

    private ListNode search(int key) {
        ListNode cur = head;
        while (cur.next != null) {
            if(cur.next.val == key) {
                return cur;
            }
        }
        return null;
    }

    @Override
    public void removeAllKey(int key) {
        if(head == null) {
            return;
        }

        ListNode prev = head;
        ListNode cur = head.next;

        while (cur != null) {

            if(cur.val== key) {
                prev.next = cur.next;
                cur = cur.next;
            } else {
                prev = cur;
                cur = cur.next;
            }
        }

        if(cur.val == key) {
            head = head.next;
        }
    }

    @Override
    public int size() {
        int count = 0;
        ListNode cur = head;
        while (cur != null) {
            count++;
            cur = cur.next;
        }
        return count;
    }

    @Override
    public void clear() {
        ListNode cur = head;
        while (cur != null) {
            ListNode curN = cur.next;
            cur.next = null;
            cur = curN;
        }
        head = null;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }
}
